Level 3

The free DNS servers listed above as Level 3 will automatically route to the nearest DNS server operated by Level 3 Communications, the company that provides most of the ISPs in the US their access to the internet backbone. Alternatives include 4.2.2.1, 4.2.2.2, 4.2.2.3, 4.2.2.4, 4.2.2.5, 4.2.2.6. These servers are often given as Verizon DNS servers but that is not technically the case.